One type of photographic processing apparatus is known as a "minilab". A typical minilab has three sections. The first section is a printer where negatives are exposed to photographic paper to record latent images on that paper. The exposed photographic paper is then fed into the second section, or processor. In the processor, the paper is treated with processing chemicals to develop the latent images so as to produce stable prints. The stable prints are then fed to the third section of the minilab, the dryer, where excess moisture is removed from the prints. As the exposed paper is being developed in the processor, the processing chemicals are consumed and have to be replenished. Tests are made periodically to check that the correct quantity and concentration of processing chemicals is present in the processor and to ensure that the chemical sections of the minilab are in balance. The tests involve feeding carefully exposed test strips into the processor section through a dedicated slot known as a test strip feed slot. Test strips are commonly about 0.3 m long and can have a series of colored strips exposed onto them. They are held flat in special holder which is attached to the test strip feed slot to ensure that the test strip is not affected by light, prior to it being fed into the processor section. Examination of the test strip after it has been developed in the processor will give an indication of whether the chemical balance in the processor is correct and whether the sections of the minilab are correctly balanced.